The following illustrates the syntax of using a column alias: SELECT columnname AS aliasname FROM table. The column alias exists temporarily during the execution of the query. A column alias allows you to assign a column or an expression in the select list of a SELECT statement a temporary name. Suppose, we have a customers table with the following columns id, first_name, last_name, country, account_status, and purchase_history. Introduction to the PostgreSQL column aliases. ![]() The CASE statement can be used when working with multiple columns to apply it to each column separately or to make new categories or flags based on the information from other columns. Summary: in this tutorial, you will learn how to use the PostgreSQL CASE conditional expression to form conditional queries. ![]() Searched CASE: To determine the result, this form uses independent Boolean expressions. Simple CASE: This form calculates the result by comparing an expression to a collection of simple expressions. There are two forms of the CASE statement in PostgreSQL: All comparison operators in PostgreSQL can be used in the condition of the Case statement. The result value corresponding to a TRUE condition is what is returned by the Postgres Case statement. It allows us to conditional login in SQL queries, which makes them more flexible and dynamic. The results, i.e., result1, result2, etc., signify the possible values that can be returned. Similar to IF-THEN-ELSE statements in other programming languages, the CASE statement in PostgreSQL expresses a condition. Suppose, we have a customers table with the following columns id, firstname, lastname, country, accountstatus, and purchase. What are PostgreSQL CASE Multiple Columns? The CASE statement can be used when working with multiple columns to apply it to each column separately or to make new categories or flags based on the information from other columns.
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